The most widely used dosage forms for oral administration include tablets and capsules. However, such dosage forms have several disadvantages. For example, it is estimated that 50% of the population have problems swallowing tablets (see Seager, 50 J. Pharmacol. and Pharm. 375-382 (1998)). In particular, it is difficult for some elderly persons to swallow tablets or capsules or to medicate children who are unable or unwilling to swallow tablets or capsules. This leads to poor or non-compliance with the treatment, and thus has a negative impact on the efficacy of the treatment.
The bitter taste of many actives also precludes medications from being easily sprinkled onto food, a commonly used method of administering medications to children. Bitter tasting drugs-incorporated into chewable tablets are typically thickly coated mostly with water-insoluble polymers, such as ethylcellulose, to taste mask the drugs through resisting fracturing of the coated drugs during tablet compression and/or during chewing and concomitant leakage of the bitter active. Consequently, substantially complete release of the drug from such chewable tablets in the gastrointestinal tract may take 2 hours or longer. More recently, orally disintegrating tablet (ODT) dosage forms have been introduced, which rapidly dissolve or disintegrate in the buccal cavity, and hence can be taken without water. Other convenient oral dosage forms include sachets and microparticle dispersions. Such medicines are convenient, particularly for the elderly and children.
Fexofenadine hydrochloride is a histamine H1 receptor antagonist, and is approved for the treatment of seasonal allergic rhinitis and chronic idiopathic urticaria. However, formulating fexofenadine is complicated by its low solubility at low pH (i.e., gastric) conditions. One typical way of addressing low solubility is to formulate the drug in ODT (orally disintegrating tablet) form. However, that approach is complicated by the bitter taste of fexofenadine hydrochloride.
U.S. Pat. No. 6,723,348 describes the preparation of an orodispersable tablet (ODT) containing fexofenadine in the form of fexofenadine granulated with additional excipients, then fluid bed coated with a polymer coating. However, the manufacturing process is relatively complex and requires multiple granulation, coating, and mixing steps.
It is an object of the present invention to provide microencapsulated fexofenadine, by a simple process, in a taste-masked immediate release form.